Final report Task 4

IEA HPP Annex 40 Bundesamt für Energie BFE IEA Heat Pump Centre iea International Energy Agency‌

Final Report IEA HPT Annex 40 Task 4

Summary IEA HPT Annex 40 Task 4

In Task 4 of the IEA HPT Annex 40, field monitorings of heat pumps in low energy and nearly zero energy buildings have been performed both in residential and in office buildings. Good performance values in the real operation of the heat pump for this application could be confirmed by the measurement. However, also various optimisation potentials could be identified based on hydraulic integration, design and control, leading to even better energy performance and cost saving potentials.

In a long term monitoring in office buildings in Germany, it was found that auxiliary source energy can make-up a large fraction of the electricity consumption. Results are in the range of 6-25%, which limits the seasonal performance and could be significantly improved with a thorough hydronic layout of the source system. Moreover, control settings for running times of pumps were optimised and energy-efficient pumps enable better use of the heat source. On the sink side, low temperature emission systems like thermally activated building systems should be connected separately in order to benefit from low supply temperatures for the heat pump operation.

Among the field monitoring also the first nZEB P&D buildings in Norway have been evaluated. The nZEB balance has been reached in a retrofitted office building, and despite high temperatures, good performance values of the heat pump have been reached. However, the design of the source system could be better adapted to the loads, which could reduce the system cost. Moreover, improvements were found in the heat recovery from the computer cooling. In a further monitoring, a CO2-heat pump for DHW heating in three retrofitted blocks of flat reaches an excellent SPF above 4 at DHW temperature of 70 °C.

In the Netherlands strategies for deep retrofitting to nZEB have been evaluated in field monitoring. The objective is to create a large market demand for nZEB retrofitting and reduce the cost by innovation and optimised building processes. The concept shall be extended also to France and the UK.

In the frame of Task 4 also first evaluations of self-consumption and load-shift options with the heat pump operation have been accomplished in two buildings in Switzerland. In a small multi-family plus energy building, self-consumption rate could be increased by 10-15% by shifting the heat pump operation from nighttime to daytime. In a second MINERGIE-A certified building with mixed residential and office use, the self-consumption of the on-site PV generation was evaluated to approximately 40% without dedicated load shifting of the heat pump operation, which is due to the good load match of PV production and office use during daytime,
so load match tends to be better than in residential buildings. Further increase is expected by the shift of the heat pump operation. Also in Canada and Japan investigations of demand response potentials show favourable values for the heat pump.

Summarising, the field monitoring results confirm that the heat pumps already reach good performance values in the application of nZEB, but performance can even be increased by system optimisations. Moreover, heat pumps are a candidate for load shifting either to increase the self-consumption of on-site PV generation or as operation reserve for grid-supportive operation. Self-consumption rates of 30% in residential buildings and 40% in office buildings could be evaluated.
Thereby, heat pumps are facilitating to reach an nZEB balance by good performance values and demand response capability, which may become an important aspect with the broader introduction of nZEB requirements for new buildings.


IEA HPT Annex 40
Final Report Task 4